1. Field of the Invention
The present invention relates to improvements in or relating to a photoelectric conversion device in which a number of semiconductor elements are sequentially arranged on a substrate in side-by-side relation and connected in series. The invention also pertains to a method for the manufacture of such a photoelectric conversion device.
2. Description of the Prior Art
There has been proposed in U.S. Pat. No. 4,315,096 a photoelectric conversion device of the type that a plurality n (n being an integer greater than one) of semiconductor elements U.sub.i to U.sub.n are sequentially formed side by side on a substrate having an insulating surface and are connected in series one after another. According to this semiconductor photoelectric conversion device, the semiconductor element U.sub.i (i=1, 2, . . . n) has a first electrode E.sub.i formed on the substrate, a non-single-crystal semiconductor laminate member Q.sub.i formed on the first electrode E.sub.i to form at least one semiconductor junction and a second electrode F.sub.i formed on the non-single-crystal semiconductor laminate member Q.sub.i in opposing relation to the first electrode E.sub.i. The second electode F.sub.j+1 of the semiconductor element U.sub.j+1 (j=1, 2, . . . (n-1)) is coupled with the first electrode E.sub.j of the semicondutor element U.sub.j through a coupling portion K.sub.j formed by an extension K.sub.j of the second electrode F.sub.j+1. The first electodes E.sub.j and E.sub.j+1 are isolated by a first groove G.sub.j, and the second electrode E.sub.j+1 extends on the non-single-crystal semiconductor laminate member Q.sub.j and the second electrodes F.sub.j and F.sub.j+1 are isolated on the non-single-crystal semiconductor laminate member Q.sub.j.
In the photoelectric conversion device mentioned above, the coupling portion K.sub.j is shown to be coupled at its surface with the first electrode E.sub.j. In this case, however, in order to obtain good contact between the coupling portion K.sub.j and the first electrode E.sub.j, it is necessary that the area of the contact portion in the lateral direction be increased. But this makes it impossible to form the photoelectric conversion device with high density.
Moreover, in the photoelectric conversion device of the abovesaid U.S. patent, it is shown that the coupling portion K.sub.j makes contact with the first electrode E.sub.j only at the outer side thereof. In this case, the contact area between the coupling portion K.sub.j and the first electrode E.sub.j is extremely small, so that good contact cannot be obtained between them. Therefore, the aforementioned prior art has the defect that a photoelectric conversion device with low electrical loss cannot be obtained with high density.
In the case of the aforementioned conventional photoelectric conversion device, the non-single-crystal semiconductor laminate member Q.sub.j+1 extends into the first groove G.sub.j. In such a case, in order to decrease leakage between the first and second electrodes E.sub.j+1 and F.sub.+1, it is necessary that the resistance of the non-single-crystal laminate member Q.sub.j+1 in the first groove G.sub.j be sufficiently higher than the resistance of the non-single-crystal semiconductor laminate member Q.sub.j+1 between the first and second electrodes E.sub.j+1 and F.sub.j+1. But this is not taken into account in the aforesaid U.S. patent. Accordingly, the conventional device cannot provide a high photoelectric conversion efficiency.
Moreover, according to the aforementioned U.S. patent, no consideration is paid to the fact that the non-single-crystal semiconductor laminate member Q.sub.j+1 is deteriorated from the side of the coupling portion K.sub.j to the side of the non-single-crystal semiconductor laminate member Q.sub.j+1 owing to the coupling portion K.sub.j during the manufacturing step of said coupling portion K.sub.j and in the long-term use of the device. Accordingly, high photoelectric conversion efficiency cannot be obtained and the photoelectric conversion efficiency is lowered by the long-term use.